Django 固定装置和 auto_now_add 日期时间字段

Question

尝试为具有 auto_now_add 日期时间字段的模型创建固定装置

created_at = models.DateTimeField(auto_now_add=True)

加载灯具时会抛出错误IntegrityError:安装灯具时出现问题，“created_at”列中的空值违反了非空约束

有没有办法让 Django 确定日期而不是手动输入日期？

[
  {
    "model": "customer.type",
    "pk": 1,
    "fields": {
      "name": "type",
      "created_by": 1
    }
  }
]

Answer 1

简单的解决方法之一是使用 default--[DjangoDoc]和 editable--[DjangoDoc]一起争论，

<b>from django.utils import timezone</b>


class Foo(models.Model):
    ...
    created_at = models.DateTimeField(<b>default=timezone.now, editable=False</b>)

上述解决方案在Django 2.1和Python 3.6环境下进行了测试和验证。

---

该方法的缺点

来自Django-Doc of DateField.auto_now_add

Automatically set the field to now when the object is first created. Useful for creation of timestamps. Note that the current date is always used; it’s not just a default value that you can override. So even if you set a value for this field when creating the object, it will be ignored. If you want to be able to modify this field, set the following instead of auto_now_add=True

这意味着，如果您手动提供任何有效的日期时间，此设置将覆盖 timezone.now() 值。